Scrollable dropdown menu with submenus in Bootstrap - css

Question

I am trying to achieve scrollable dropdown menu with sub-menus. I used the css from this post to have sub-menus in bootstrap 3. The problem is that the sub-menu is hidden within the container or is visible with a horizontal scrollbar within the container.
Here is what I have http://www.bootply.com/1OsPZq7WJC
For reference, HTML:
<div class="btn-group">
<button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown">Scrollable Menu <span class="caret"></span></button>
<ul class="dropdown-menu scrollable-menu" role="menu">
<li>Action</li>
<li class="dropdown-submenu">Submenu
<ul class="dropdown-menu">
<li>Action 1</li>
<li>Action 2</li>
<li>Action 3</li>
<li>Action 4</li>
<li>Action 5</li>
<li>Action 7</li>
</ul>
</li>
<li>Action</li>
<li>Another action</li>
<li class="dropdown-submenu">Submenu
<ul class="dropdown-menu">
<li>Action 1</li>
<li>Action 2</li>
<li>Action 3</li>
<li>Action 4</li>
<li>Action 5</li>
<li>Action 7</li>
</ul>
</li>
</ul>
</div>
And CSS:
.scrollable-menu {
height: auto;
max-height: 200px;
overflow-x: visible;
overflow-y: scroll;
}
.dropdown-submenu{position:relative;}
.dropdown-submenu>.dropdown-menu{top:0;left:100%;margin-top:-6px;margin-left:-1px;-webkit-border-radius:0 6px 6px 6px;-moz-border-radius:0 6px 6px 6px;border-radius:0 6px 6px 6px;}
.dropdown-submenu:hover>.dropdown-menu{display:block;}
.dropdown-submenu>a:after{display:block;content:" ";float:right;width:0;height:0;border-color:transparent;border-style:solid;border-width:5px 0 5px 5px;border-left-color:#cccccc;margin-top:5px;margin-right:-10px;}
.dropdown-submenu:hover>a:after{border-left-color:#ffffff;}
.dropdown-submenu.pull-left{float:none;}.dropdown-submenu.pull-left>.dropdown-menu{left:-100%;margin-left:10px;-webkit-border-radius:6px 0 6px 6px;-moz-border-radius:6px 0 6px 6px;border-radius:6px 0 6px 6px;}

Answer 1

You can't force the page to adopt the height of the drop down menu unless you define a specific height. Here is the css you need to add for a full page height.
body{
height:100vw;
}
Fiddle.